Update actions/checkout action to v3

Author: renovate-bot

.github/workflows/pr.yml

@@ -14,7 +14,7 @@ jobs:
       with:
         go-version: 1.17.x
     - name: Check out code into the Go module directory
-      uses: actions/checkout@v2
+      uses: actions/checkout@v3
     - name: run tests
       run: |
         export GOPATH=$HOME/go